A biface and blade core efficiency experiment: implications for Early Paleoindian technological organization

Early Paleoindians often are described as highly mobile hunter–gatherers who employed lithic technologies designed to minimize stone transport costs. We experimentally reduced blade and bifacial cores and found both reduction strategies to be equally efficient for the production of useable flake blanks. Further, when compared to similar core reduction experiments, the results of this study showed no significant differences in core efficiency between bifacial, prismatic blade, and wedge-shaped blade core reduction. Biface and blade cores with initial weights greater than 1000 g produced useable flakes as efficiently as informal cores. However, bifacial and blade core efficiency decreased with initial core weight. When considered in terms of Early Paleoindian technological organization, differences in core efficiencies suggest that Folsom groups employed core reduction strategies designed to minimize stone transport costs, but Clovis groups did not.     

Experimental analysis of the practical limits of lithic refitting

We report on the results of an experiment aimed at determining the effects of experience/aptitude, lithic reduction type (biface v. core), and flake size cut-offs on different rates of success in refitting studies. We found that experience matters, but that there can be large differences in aptitude for refitting; that cores are easier to refit than bifaces; and that the effort of refitting increases considerably for flakes smaller than 5–6 g. We propose the use of an asymptotic equation fit to a cumulative curve as a way to determine when a study has reached the point of diminishing returns for a given flake size cut-off, and to help determine differences in aptitude for refitting.     

Fracture markings from flake splitting

When a flake is split longitudinally during its detachment, it can leave several kinds of fracture markings, termed here split marks, on the flake scar. Observations from contemporary knapping are considered together with mechanics and fractography for understanding the formation of the split marks. These markings on a negative flake scar can indicate the splitting of a flake during its detachment. Recognition of flake splitting is of archaeological interest especially for technologies where the flakes were utilized.     

Milky Quartz Bipolar Reduction and Lithic Miniaturization: Experimental Results and Archaeological Implications

We present experimental data examining the energetics and identification of axial bipolar reduction in contexts of lithic miniaturization on milky quartz. These experiments answer two specific questions. First, does bipolar reduction provide any benefits over freehand reduction? Second, can axial bipolar reduction be distinguished from freehand reduction? Our data show that bipolar reduction requires significantly less time to reduce a percentage unit of core mass and to produce a millimeter of cutting edge on milky quartz than freehand reduction. Milky quartz bipolar reduction surpasses even the cutting edge production efficiency of obsidian pressure blades. We outline a series of quantitative criteria for identifying bipolar cores and flakes. Our results show that bipolar cores and flakes can be distinguished from those produced using freehand reduction by quantifying platform crushing, distal flake rebound scars, bulb shearing, as well as axial, bipolar, and splintered flake terminations. Our results challenge the widely held perceptions about the wastefulness of bipolar reduction and provide clear guidelines for identifying this reduction strategy in archaeological milky quartz assemblages.     

Technology based evolution? A biometric test of the effects of handsize versus tool form on efficiency in an experimental cutting task

The use of stone cutting tools opened a novel adaptive niche for hominins. Hence, it has been hypothesised that biomechanical adaptations evolved to maximise efficiency when using such tools. Here, we test experimentally whether biometric variation influences the efficiency of simple cutting tools (n = 60 participants). Grip strength and handsize were measured in each participant. 30 participants used flint flakes, while the other 30 used small (unhafted) steel blades. Variations in basic parameters of tool form (length, width, thickness, cutting edge length) were recorded for the 30 flint flakes. It was ensured that mean handsize and strength in each participant group were not significantly different to investigate the effect of tool variation. The experimental task required cutting through a 10 mm-diameter hessian rope. Cutting efficiency was measured using both ‘Number of cutting strokes required’ and ‘Total time taken’. Results show that both efficiency measures were significantly correlated with handsize using all 60 participants. However, no significant differences were found between the flake and blade groups in terms of mean efficiency. Nor was any significant relationship found between tool form parameters and efficiency in the flint flake group. We stress that our results do not imply that tool form has no impact on tool efficiency, but rather that – all other things being equal – biometric variation has a statistically significant influence on efficiency variation when using simple cutting tools. These results demonstrate that biomechanical parameters related directly to efficiency of use, may plausibly have been subject to selection in the earliest stone tool-using hominins.     

A geometric morphometric relationship predicts stone flake shape and size variability

The archaeological record represents a window onto the complex relationship between stone artefact variance and hominin behaviour. Differences in the shapes and sizes of stone flakes—the most abundant remains of past behaviours for much of human evolutionary history—may be underpinned by variation in a range of different environmental and behavioural factors. Controlled flake production experiments have drawn inferences between flake platform preparation behaviours, which have thus far been approximated by linear measurements, and different aspects of overall stone flake variability (Dibble and Rezek J Archaeol Sci 36:1945–1954, 2009; Lin et al. Am Antiq 724–745, 2013; Magnani et al. J Archaeol Sci 46:37–49, 2014; Rezek et al. J Archaeol Sci 38:1346–1359, 2011). However, when the results are applied to archaeological assemblages, there remains a substantial amount of unexplained variability. It is unclear whether this disparity between explanatory models and archaeological data is a result of measurement error on certain key variables, whether traditional analyses are somehow a general limiting factor, or whether there are additional flake shape and size drivers that remain unaccounted for. To try and circumvent these issues, here, we describe a shape analysis approach to assessing stone flake variability including a newly developed three-dimensional geometric morphometric method (‘3DGM’). We use 3DGM to demonstrate that a relationship between platform and flake body governs flake shape and size variability. Contingently, we show that by using this 3DGM approach, we can use flake platform attributes to both (1) make fairly accurate stone flake size predictions and (2) make relatively detailed predictions of stone flake shape. Whether conscious or instinctive, an understanding of this geometric relationship would have been critical to past knappers effectively controlling the production of desired stone flakes. However, despite being able to holistically and accurately incorporate three-dimensional flake variance into our analyses, the behavioural drivers of this variance remain elusive.     

Large Kombewa flake production in north Oman

In this paper we present the results of surveys carried out in February 2016 along a palaeo‐drainage system near the village of Bisyah. We report first on the geological prospection, which was our main goal, and then present our discovery of the only known localities in north Oman of large Kombewa flake production (>10 cm up to 20 cm). Among the scatter of artefacts, we found cores and large Kombewa flakes with two opposed bulbs of percussion, a technology that had not been known in this region until now. In spite of the local features, the typo‐technological traits of the artefacts suggest that at least part of them resemble in some way the Acheulean techno‐complex, but there are still many questions remaining on the age of these artefacts.     

Estimating original flake mass from 3D scans of platform area

This study confirms the increased capacity to predict flake mass that arises from more accurately measuring surface area in three dimensions using a digital scanner. We also reveal the existence of significantly different relationships between platform area and flake mass for flakes with different platform types and ventral and dorsal morphologies. These different relationships between platform surface area and mass have not been previously identified, and reveal the complexity of platform/mass relationships. Using multivariate regression of 3D platform surface area and external platform angle we improve the accuracy of predictions of original flake mass. We propose a method for studying reduction intensity on retouched flakes, based on comparing predictions of the initial mass of the flake with measurements of the mass following retouching to estimate the amount of mass removed through retouching. We name this approach the Initial-/Terminal-Mass Comparison, or ITMC. Our experiments demonstrate that the capacity of the 3D platform scans to predict flake mass, and by implication the capacity of the ITMC to estimate mass loss, rivals or exceeds the capacity demonstrated for existing reduction measures.     

Introducing a new experimental design for controlled studies of flake formation: results for exterior platform angle,platform depth,angle of blow,velocity, and force

Potential variables that underlie variation in flake size, and in some instances shape, are investigated in a newly designed experiment. This new design, which utilizes glass cores molded to a specific shape, results in flakes that are identical to archaeological ones. Variation in exterior platform angle, platform depth and angle of blow all directly affect flake size, and in the case of exterior platform angle, flake shape as well (in spite of constant core surface morphology). In treating velocity and force independently, neither is found to affect flake size or shape. These results have implications for understanding different strategies that flintknappers may employ to control the size of their flake products.     

A method for estimating edge length from flake dimensions: use and implications for technological change in the southern African MSA

This paper presents a method for estimating edge length from flake dimensions. Comparison of estimated values with data from measured flake edges demonstrates the robusticity of the method. Building on the work of Braun (Braun, D.R., 2005. Examining flake production strategies: examples from the Middle Paleolithic of Southwest Asia. Lithic Technology 30, 107–125; Braun, D.R., Harris, J.W.K., 2003. Technological developments in the Oldowan of Koobi Fora: innovative techniques of artifact analysis and new interpretations of Oldowan behavior, in Mora, R., de la Torre, I. (Eds.), Oldowan: Rather More than Smashing Stones. Treballs d’ Arqueologia 9, pp. 132–144) this estimate is used to generate an edge length to mass value for complete flakes—taken to be a proxy for flaking efficiency. It is shown that this value is useful in tracking the onset, variability and decline of a well known technological phase—the Howiesons Poort of South Africa. The results suggest that the Howiesons Poort was a time in which flaking efficiency was emphasised. Furthermore, comparison of upper limits of edge to mass values for different raw materials may provide an insight into changes in raw material selection.     

The oldest human traces north of the Carpathians (Kończyce Wielkie 4, Poland)

In the area of the Kończyce Wielkie quarry (middle-southern Poland), the Quaternary deposits of different genesis crop out. The lower fluvial series is overtopped with the glacigenic sediments occurring below the Matuyama–Brunhes boundary. This ice-sheet advance is correlated with the Günz and with the oldest traces of glaciations in Western Europe. Culture materials were located within layer of fluvial sands with fine-grained gravels, below the boulder pavement and diamicton – interpreted as till. Raw materials inventory are local flint and hornstone, also foreign flint, hornstone, quartzite, opalite and gneissose granite. The inventory contained macrolithic and microlithic cores, flakes and tools. The tools are made from pebbles, flakes and microlithic-flakes.     

The relative effects of core surface morphology on flake shape and other attributes

It is long been thought that many flake attributes, including both size and shape, are largely due to the morphology of a core’s flaking surface, yet this has never been tested under strictly controlled conditions. Using molded glass cores with surface morphologies that highly resemble prehistoric ones, this experiment demonstrates that while core surface morphology does exhibit some influence on flake size and shape, a high degree of variation in flakes produced with the same core surface morphology shows that the effects of other independent variables, such as exterior platform angle and platform depth, have an even stronger effect. A major implication of these results is that current approaches to reconstruct prehistoric knapping strategies are overlooking significant sources of variation.     

Dogs,divers, deer and diet. Stable isotope results from Star Carr and a response to Dark

We here respond to Dark's [Dark, P., 2003. Dogs, a crane (not duck) and diet at Star Carr: a response to Schulting and Richards. Journal of Archaeological Science 30, 1353–1356] criticisms of our previous paper [Schulting, R.J., Richards, M.P., 2002. Dogs, ducks, deer and diet: a reappraisal of the stable isotope evidence on early domestic dogs from the Vale of Pickering, north-east England. Journal of Archaeological Science 29, 327–333] in which we supported the previous interpretation of stable isotope data from the Seamer Carr dog [Clutton-Brock, J., Noe-Nygaard, N., 1990. New osteological and C-isotope evidence on Mesolithic dogs: companions to hunters and fishers at Star Carr, Seamer Carr and Kongemose. Journal of Archaeological Science 17, 643–653] as indicating a marine-influenced diet. Additional isotopic data are presented on fauna from Star Carr, most importantly from two piscivorous diving birds. These new data further support the original contention that marine protein is the most likely source of the elevated carbon and nitrogen isotope values seen in the Seamer Carr dog. In addition, cutmarks on the humerus of a Brent goose, and the presence of an additional element (right femur) attributable to the previously known adult dog from Star Carr, are noted for the first time. Two new AMS determinations are presented for Star Carr, placing an adult dog in the period 9680 ± 55 BP (9270–8840 cal BC) and a subadult dog somewhat later at 9342±41 BP (8735–8475 cal BC). Unlike Seamer Carr, both dogs show entirely terrestrial (non-marine) diets.     

Flake scar patterns of Clovis points analyzed with a new digital morphometrics approach: evidence for direct transmission of technological knowledge across early North America

Clovis points are the principal diagnostic artifacts of a Clovis complex that spread across North America between ca. 11,050–10,800 radiocarbon years before present. Clovis may be the best documented Paleoamerican culture in North America, but much remains to be learned about the movement and interactions of Clovis peoples. Similarities among Clovis points from geographically diverse locations have led some researchers to suggest that a uniform projectile point technology existed across North America during Clovis times. Others have rejected this idea, proposing local and independent technological adaptations to different regional environments. To investigate these ideas, we used digital morphometrics to analyze 50 Clovis points from nine different contexts. First, 3D surface models of the points were created with a portable laser scanner. Next, these models were digitally cross-sectioned through both faces, yielding two-dimensional isoheight contours of flake scar patterns that reflect the original reduction techniques used to shape the projectile points. In the final step, the contours were transformed with elliptic Fourier analysis into Fourier coefficient series, and patterns of variation and symmetry were explored with principal components analysis. When compared to modern Clovis point replicas made by an expert knapper, the flake scar contours of the ancient Clovis points showed little morphological variation and a large degree of bifacial symmetry. Our results support the existence of a widespread standardized “Clovis” knapping technique, most likely transmitted through direct interaction between knappers from different groups.     

Measuring core reduction using 3D flake scar density: a test case of changing core reduction at Klasies River Mouth,South Africa

A new core reduction index is presented, calculated as the ratio of flake scar number to 3D surface area (SDI). The index is tested experimentally on five types of core (blade, discoid, Levallois, biface and multiplatform cores) and then applied to the core assemblages from five sub-stages of the Middle Stone Age at Klasies River Mouth, South Africa. Preliminary results indicate that the SDI possesses the desirable attributes of a successful reduction index and is a significant improvement on traditional proxy measures of core reduction. The results of the archaeological case study confirm previous untested observations that cores from the Howiesons Poort and MSAIII sub-stages are more heavily reduced than preceding and following stages, and that local and exotic raw materials as well as different types of cores are all more heavily reduced during these periods. The SDI fills a significant lacuna in available core reduction measures.     

Measuring prehistoric mobility strategies based on obsidian geochemical and technological signatures in the Owens Valley,California

We compare the organization of obsidian flaked stone technologies in two different time periods at CA-INY-30, a village site in southern Owens Valley, eastern California. Previous archaeological studies suggest a reorganization in settlement patterns between the Newberry (ca. 3500–1500 BP) and Marana (ca. 650-contact) periods, from a highly mobile to a more residentially sedentary one. New geochemical data, based on laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses of obsidian artifacts associated with discrete house floors, support this basic settlement model, but reveal new detail in how people moved across the landscape and accessed, extracted, reduced and used obsidian resources. In the earlier Newberry period, there is no relationship between flake size and distance-to-source, and the falloff curve relating frequency of obsidian against distance is more gradual, as expected, but contrary to our expectations, source diversity is not higher. These factors suggest extremely high mobility, but also selective extraction of particular sources. Newberry obsidian may have been acquired by groups of hunters who embedded quarrying within long-distance trips to distant hunting grounds, and subsequently transported bifacial cores to base camps. By contrast, Marana patterns show strong relationships between flake size and distance from source and steeper fall-off curves, suggesting groups acquired their obsidian primarily from closer sources, likely via exchange networks. At the same time, geochemical diversity, especially among smaller resharpening flakes, is higher in the Marana period, highlighting the wide-ranging conveyance systems through which obsidian moved.     

Evaluating morphological variability in lithic assemblages using 3D models of stone artifacts

Technological and morphological variability in lithic artifacts is commonly used to identify taxonomic entities in Paleolithic research contexts. Assemblages are mainly studied using either linear distance measurements or qualitative assessments of morphologies. Here, we present a method to quantify morphological variability in lithic artifacts using 3D models of stone artifacts. Our study on the sequence of the Upper Paleolithic layers V–I from the site Yabroud II in western Syria, demonstrates that utilizing 3D models provides a new insight into the variability of lithic technologies. We use quantitative data on convexities, twist and scar patterns on cores and blades, attributes previously not readily quantifiable, to trace technological change through the archaeological sequence. We are able to identify differences and translate these findings into a grouping of the layers. While layers VI–II are characterized by technological continuity and were grouped together, layers V and I can be separated from this group and represent technologically different groups chronologically before and after. Our results demonstrate the potential of 3D models for studying morphological variability in lithic assemblages.     

Patterning in procurement of obsidian in Chaco Canyon and in Chaco-era communities in New Mexico as revealed by X-ray fluorescence

X-ray fluorescence analysis of obsidian artifacts from sites located in Chaco Canyon and from three Chaco-era communities in New Mexico permits determination of their geological origin. These source data are used to describe patterning in obsidian procurement in sites located in Chaco Canyon dating from A.D. 500–1150, and in a three non-Canyon communities occupied during the period of Chaco Canyon's regional prominence (ca. A.D. 875–1150). These data demonstrate that the most proximate sources generally dominate the sourced obsidian assemblages from sites of all periods, but also suggest differences in procurement patterning both over time and across space. Within Chaco Canyon, there is a notable shift from Mount Taylor obsidian to use of Jemez Mountains sources over time. These data also suggest that earlier analyses of obsidian from sites in Chaco Canyon misidentified some obsidian artifact sources; these new data indicate the central areas of disagreement and provide a revision of procurement patterning. In the Chaco-era communities located outside Chaco Canyon, procurement patterning diverges. The Blue J community shows an increase in use of the nearby Mount Taylor source over time. Two communities located toward the southern extent of the Chaco great house distribution reveal a markedly distinct procurement pattern, obtaining nearly all of their obsidian from southern sources largely unrepresented at Chaco Canyon. Combined, these data provide new insights into raw material procurement and artifact production at sites in Chaco Canyon, and in communities occupied during the Chaco Phenomenon, the period of the Canyon's greatest regional influence.     

Radiologic proof for the Iceman's cause of death (ca. 5’300 BP)

A possible cause of death of the Iceman – a ca. 5’300 BP natural human glacier mummy from the Tyrolean Alps – is an intrathoracic stone arrowhead. The aim of this study was to prove radiologically his enigmatic cause of death. In August 2005, the Iceman underwent his first multislice computed tomography examination. As the main pathologic finding, the left dorsal subclavian artery contures shows a 13 mm-long part where the vessel wall is damaged and a 3 mm-long irregular pseudo-aneurysm – a typical complication of a laceration of the subclavian artery. In the surrounding soft tissue a large haematoma is visible. Historic records highlight the fatal destiny of subclavian artery injuries e.g. due to massive active bleeding and shock-related cardiac arrest. Therefore, the Iceman's cause of death by an arrowhead lacerating among others the left subclavian artery and leading to a deadly hemorrhagic shock can be now postulated with almost complete certainty, especially when taking the environmental (3’210 meters above sea level) and historic (5’300 BP) settings into account.